Emerging evidence from laboratory researches has highlighted the bioactivity of food
melanoidins and
melanoproteins. Whilst such studies have been carried out with different in vitro systems, information about
melanoidins absorption and bio-availability are scarce. However, they are generally considered as poorly absorbable and bio-available compounds. Therefore, we present a review in which the gastro-intestinal tract is hypothesized to be the main site of action of food
melanoidins and
melanoproteins biological activity. We described recent data supporting this hypothesis both in vitro model systems and in vivo. Importantly, we focused this review only on the effect of
melanoidins and
melanoproteins extracted from food. Most of the studies had been carried out using water-soluble
carbohydrate-based
melanoidins isolated from different food sources (beer, barley
coffee,
coffee). In bakery products,
melanoidins are
protein-based structure (
melanoproteins) which are largely insoluble in water. Dietary
melanoidins and
melanoproteins have been demonstrated to exert in vitro
antioxidant and
metal chelating ability in the gastro-intestinal tract reducing the formation of
lipid hydroperoxides and advanced
lipid oxidation end products during the digestion of meat. The reduction in the formation of these pro-atherogenic compounds has been shown to be followed by a decrease in their absorption in human volunteers. Food
melanoidins have also shown in vitro anti-caries and
prebiotic activities. We conclude by underlining the possible role of food
melanoidins in the prevention of gastro-intestinal tract
cancers. We hope this review will stimulate further research on food
melanoidins and their
biological activities in the gastro-intestinal tract.